The scheduled lift-off of Nasa's space shuttle Endeavour was delayed at the weekend after lightning struck the launch pad. A major electrical storm that struck near the Kennedy Space Centre in Florida delayed Saturday's launch, which is the fourth delay for the space station construction mission. The launch team came within minutes of sending Endeavour and seven astronauts to the international space station. "We got the vehicle ready, and the weather unfortunately did not co-operate with us today," launch director Pete Nickolenko told the seven astronauts aboard Endeavour. Nasa has until Tuesday, possibly Wednesday, to launch Endeavour with the final piece of Japan's space station lab. Otherwise, it will have to wait until the end of July because of a Russian supply ship that's awaiting lift-off. Three previous launch attempts were scrubbed due to potentially hazardous fuel leaks, apparently caused by a misaligned plate linking a hydrogen gas vent line with the external fuel tank.